Kronos was the leader of the Four Horsemen. Along with Methos, Silas and Caspian, he spread terror across two continents in the Bronze Age, killing while roaming the land and destroying everything in their way, just for the pleasure of it all.
In November 1996, Kronos resurfaced in the city of Seacouver. He tried to reunite his infamous brethren, The Four Horsemen again. The Immortal female Cassandra, a former slave of The Four Horsemen was battling Kronos when Duncan MacLeod came across them. It was then that Duncan MacLeod discovered the dark past of his close friend, the wily and peace-loving Immortal Methos. For centuries, Methos was one of the infamous Four Horsemen. He destroyed, pillaged and plundered a myriad lands across the world, right alongside them.

Cassandra and MacLeod decided that all four of them had to be killed, though MacLeod still found it difficult to see his friend as an enemy. The two of them followed a trail laid by Methos to Bordeaux, where they faced the Four Horsemen.

Kronos and Caspian were defeated after fierce and drawn-out battles by Duncan MacLeod (who had known Kronos as the vicious killer and outlaw Melvin Koren in the American Old West). The Immortal Methos, who allied himself with Duncan MacLeod, beheaded the violent yet slow-witted Silas, his only true friend among The Four Horsemen. Cassandra then tried to kill Methos, her former captor, but was convinced by MacLeod to let him live.

The character Kronos would also appear as an impersonation by the powerful demon Ahriman, a formidable foe of Duncan MacLeod, in the episodes Archangel and Armageddon. He would make one last appearance in the series final episodes, 'To Be/Not To Be', in which a world without Duncan Macleod saw Kronos and Methos re-form The Horsemen, who were at war with James Horton's Hunters, who had seized control of the Watchers from Joe Dawson.

Methos was first introduced in the Highlander episode "Methos". It was originally planned to have him die at the end of the two-parter “Finale” episode, but the writers saw potential in the character and kept him.[1]

Methos, when first introduced during Season 3, was portrayed as the "Oldest of the Immortals”. He claims he is roughly 5000 years + old,[2][3] the approximate date he took his first head, but admits that “[b]efore that, it all starts to blur.”[2]

According to the series, Methos had been keeping journals chronicling his life.[2] Because of these journals, he was considered one of the Watcher Organization's greatest mysteries. His existence was doubted and questioned for many centuries. Methos (under the guise of Watcher Adam Pierson) was assigned to the writings chronicling the legendary Methos' past. These journals documented - with varied accuracy - much of his life. In doing so, he became somewhat of an off-field agent for The Watchers and was able to keep tabs on other Immortals that he preferred to avoid. That changed when two Watchers died at the hand of Kalas, an evil Immortal.[2]

During the third season Joe Dawson, Duncan's Watcher and close friend, realized that Kalas was looking for Methos. Joe knew that with Methos's Quickening, Kalas could be unstoppable. Both Kalas and MacLeod raced to be the first to find Methos. Duncan's search led him to seek out the Watcher known as "Adam Pierson." When they first met, Duncan immediately sensed that Adam was an Immortal. Through his conversation with Adam, MacLeod realized that Adam was Methos.[2] Duncan eventually killed Kalas on top of the Eiffel Tower in the season's finale.[4] Methos and Duncan become friends.

During the Bronze Age, Methos rode alongside three other immortals: Silas, Caspian, and Kronos, who were known as The Four Horsemen[5] and who had plundered and raped across villages on two continents.[5][6][7] Kronos tracked down Methos in order to get to MacLeod.[5]

Cassandra, an Immortal love interest of Duncan's and who was also tracking Kronos, pointed out to Duncan that Methos was actually Death. She claimed he had enslaved her after destroying her village thousands of years ago.[5]

Methos decided to flee, but Duncan caught him before he left. When asked whether Cassandra's accusations were true, Methos responded:

I killed. But I didn't just kill fifty, I didn't kill a hundred. I killed a thousand. I killed TEN thousand! And I was good at it. And it wasn't for vengeance, it wasn't for greed. It was because... I liked it. Cassandra was nothing. Her village was nothing. Do you know who I was? I was Death. Death — Death on a horse. When mothers warned their children that the monster would get them, that monster was me. I was the nightmare that kept them awake at night. Is that what you want to hear?! The answer is yes. Oh, yes.[5]

In that moment, Duncan decided to put an end to their friendship.[5] Methos persuaded Kronos to put the band together again since he knew where both Caspian and Silas were. Kronos took the opportunity, relishing the idea of world domination again. In the end, Methos allied himself with Duncan MacLeod to destroy the Horsemen. The two defeated Kronos and Silas together in the same area, resulting in a powerful Double Quickening. Their friendship, however, still remained strained.[6]

Methos returned again in Season 6, the last season for the television series. During the episode "Indiscretions", he learns he's being chased by an obsessive Immortal named Morgan Walker. Walker hated him for having had an affair with his slave 200 years ago. Methos, trying to hide from Walker who had tracked him down, looked for information in the Watchers' computer database. Joe Dawson was angry when he found out that Methos was only trying to save his own life by hacking into Joe's files, instead of explaining his whereabouts one year earlier. Although Joe and Methos' friendship was shaky, together they helped rescue a rookie Watcher and also Joe's illegitimate daughter, Amy Thomas. Their adventure helped them to rekindle their friendship and Methos was able to defeat Walker.[8]

During the series finale, Duncan MacLeod was thrown into another reality where he had never been born. In this reality, Methos had a lover named Jillian, who was killed by The Watchers (who were trying to kill him). He survived their attack due to Kronos saving him. The event made him swear revenge to all the Watchers. He gathered together the Four Horsemen and also Richie Ryan, but the Watchers killed Silas and Caspian. Methos later killed Richie, who couldn't bring himself to kill Joe Dawson on Methos's orders. Duncan MacLeod saw this with the help of Hugh Fitzcairn's spirit, and tried to stop all of it. He fought Methos and killed him in revenge for Richie's death. In the same instant that Duncan executed the killing stroke, he returned to his original reality, where Methos tried to wake him up. In the end, it was the advice of Methos that put Duncan MacLeod back into The Game once more.[9]

According to the book An Evening at Joe's, he was born in ancient Egypt and was the second son of three boys and two girls, making him one of the few ancient immortals not known to be a foundling. When he was approximately 35 years old, the oasis at which his family lived ran dry. He had accompanied his family as they traveled to another oasis and experienced his first death when a sandstorm trapped them before they reached their destination. A Bedouin tribe found him and housed him for a while, teaching him the ways of survival in the desert. He stayed with them for many years, until it was evident that he wasn't aging. By the time he was an estimated 603 years old, he began to meet others that were like him. He then realized that there were many Immortals besides himself. He learned some facts of immortality from Menahem, an Immortal whom Methos considered ancient at the time. It was also during this time in his life that he took his first head, from another immortal named Joseph.[7]

During time he spent in ancient Egypt an Immortal pharaoh named Djer took him under his wing. Methos soon learned that the Pharaoh had his nomad wife killed during a smiting of Sinai (the killing of all nomads). Angered at Djer, Methos buried him alive inside a sarcophagus deep within a tomb. He claimed Djer's throne and became Pharaoh of Egypt.[10]

Methos is portrayed as having a dry sense of humor,[2][11] a pessimistic view on life,[12] a witty repartee,[13][14][15][16] and a somewhat loyal devotion to his friends.[8][14][15] He's also very untrusting of people,[11][12] has been accused by others as putting himself first,[6][8] as being arrogant,[12] and as being manipulative.[5][16] When in conversations with both Duncan and Richie, his manner is often comparable to that of a sarcastic old man (who hasn't managed to die yet), with his tendency to be right being rather annoying to his friends.[14] Ironically, Methos looks younger than most Immortals in the series, being physically stuck at ca. 25-35, causing his mannerisms to clash with his appearance. He has also the habit of saying "yes" after each sentence if he wants to emphasize whatever he is saying right now.[14] Methos is a method actor, being able to completely become whatever identity he has taken on at the time, but is able to switch to a far darker tone within a moment, surprising most people, and making them unsure of what to think of the "old man".[14]

Methos avoids battle and, for the most part, other Immortals whenever possible.[2][3][11][15] In tune with this, it is hardly surprising that his Ivanhoe-style sword was quite subdued, simply serving the purpose of keeping him alive.[2] He sleeps with his sword under his bed and sometimes carries a handgun.[17] He rarely participated in The Game (his preference was to observe rather than fight),[2][18] preferring to remain a legend so few would come looking for him.[16] Whenever he perceived that there was a great danger nearby, he had a habit of suddenly disappearing for a while.[3][5][8][19] However, even though he preferred to stay in the shadows, he could still defend himself when needed, and with time, his admittedly rusty skills would come back to life.[2][6][8][14] In combat, he showed a deviousness and ruthlessness unmatched by most of his associates not considered evil, using underhanded tactics to win, such as a surprise attack with an additional dagger while locking his opponent's blade in defense.[17]

He considered opera music to be boring[15] and he liked Bruce Springsteen, Queen,[2] and other music as well. He collected things, mostly antiques that many people considered to be junk, claiming that he thought some of the "junk" could be his from the past.[12] He has also commented that although he knew most of everything in life, he was a bit weak in pop-cultural matters.[5]

Methos often used the name "Adam" in some way in most of his aliases (likely a reference to the Biblical Adam and his extreme age). In the early 19th century, one of his aliases was “Benjamin Adams.”[20] He was also known as “Ben Adams” when he moved to Arizona around 1860.[7] Between 1980 and 1996 he was known as “Adam Pierson.”[2] He also made rather frequent jokes and references to his age; Duncan and Joe often simply called him "Old Man". He is one of the few immortals who count their lifetimes in millennia, instead of centuries.

When an impostor calling himself Methos appeared he thought it was flattering, and was happy to let someone else be hunted for a while.[16]

At first, Alexa refused his proposition of dating, because she didn't want to disappoint him as she was dying. However, Methos was persistent, and waited for her under the rain and asked her out on a date. He mentioned to Alexa that the reason for asking her on a date was "[b]ecause the alternative is unthinkable."[13] In his quest to make her feel alive even though she was dying, he wanted to make her dream come true by traveling the world.[7][13][22]

During their travels, Alexa became gravely ill. Methos wanted to use the Methuselah's Stone, rumored to be able to make a person Immortal, to save Alexa. He tried to steal it, with help from Amanda. Methos failed to retrieve the stone due to the intervention of the Watchers.[18] Methos remained at Alexa's side until she died of her illness.[11] It was her strength that taught Methos' humanity's will to live despite the fact they would ultimately die. She was the person that opened his eyes, at the same time, cursed at the fact that with the power of immortality, he would have to live with the fact that he must watch her suffer and die. A thing that Duncan knows too well.

Amanda and Methos had similar personalities in the series. Both are shown to be cunning, to think of themselves as a priority, and both remain loyal to their friends. When Amanda was captured by a nemesis of Duncan MacLeod's, Methos offered to help, saying he was “...fond of the little vixen [him]self.”[23]

She seemed to know Methos from earlier times and she also helped him when he tried to steal the Methuselah crystal.[18] When he failed, Amanda gave him a heartfelt hug and words of encouragement.[18]

Methos believes very strongly in Duncan MacLeod[2][21] going so far as to offer him his head to defeat an evil Immortal.[2] He often refers to MacLeod as a “Boy Scout”[24] and tries to keep him out of trouble as much as possible.[12] Often, Methos will take on the opposite view of Duncan about situations, appearing to play devil's advocate.[12][16] Although at times this quirk rubbed Duncan the wrong way, their friendship still remained relatively strong during the series and into the movies (even despite the events of “Comes A Horseman” and “Revelation 6:8”), as Duncan often seeks out Methos for help and guidance.[21][25]

Nothing is known of his Watcher assignments, indeed, considering that he stayed among them for at least 200 years and being sought for likely even longer, it is presumable that he next-to-never had a watcher.
During his time staying with the Watchers, he was essentially his own Watcher, tasked with locating himself (and thus preventing this altogether).

Sometime during his life, when realizing that for being the oldest Immortal, he was a primary target for all the other Immortals, he removed himself from The Game. He hid within The Watchers, where he was put in charge of locating himself, essentially making himself his own watcher.[2] When Duncan MacLeod meets him in 1995, Methos had not taken a head for roughly 200 years; however, his sword skills were not diminished, although he admitted to be a little rusty, and later on also admitting he lacked the fire/passion to continue fighting at all.

Silas was an Immortal known for great evil as a member of "The Four Horsemen"; a group of Immortals who raped and killed across two continents during the Bronze Age. The gruff-voiced Silas loves to do nothing more than kill, especially with the battle axe he wields. The Four Horseman came across a village where pre-Immortal Cassandra lived. The Four Horsemen killed everyone in her village. Silas and the others took trophies of their kills. Silas and Caspian were fighting over a blanket. Kronos, the leader of the Horsemen used his sword to split the blanket in two. Silas was good friends with fellow Horseman, Methos.

Silas then lived in Ukraine, hiding in the woods for many centuries. In November 1996, he was chopping wood one day and sensed the presence of other Immortals: Kronos and Methos. The Four Horsemen are united after they got Caspian out of an insane asylum. They went to an abandoned submarine base in Bordeaux, France. Silas didn't realise how much times had changed, however, still wanting to ride on horseback to kill. Kronos makes plans to rule the world by developing a virus. Silas wanted one of the monkeys in the cage as a pet. Later on, Kronos sent Silas and Caspian to deal with Duncan MacLeod. Duncan beheaded Caspian and escaped while Silas returned to their hideout. Duncan goes there to rescue Cassandra, captured by the Horsemen. Duncan ends up fighting Kronos, and Silas goes to behead Cassandra, but Methos stops Silas and fights him. Silas is beheaded by Methos at the same time Duncan beheads Kronos. Duncan and Methos receive a Double Quickening. Methos is grief-stricken for what he had done as he saw Silas the closest thing to a brother.

An immortal, Caspian was born sometime in the 13th century BC. He was a member of the Four Horsemen, a group of mounted riders who terrorized, killed, and burned villages in two continents during the Bronze Age. He and fellow member Silas were always fighting. When they raided the village where Cassandra lived, Caspian and Silas fought over a blanket. Kronos, the leader of the Four Horsemen, ended up splitting the blanket so they could each have part of it.

Centuries after his stint in the Four Horsemen, Caspian, under the alias Evan Caspari, became a serial killer in Romania. No one knows how many people he killed; he kept body parts in his basement, garden and his freezer. Caspian was arrested and sent to an asylum for the criminally insane outside of Bucharest, Romania where he was kept chained in a cell. Years later, in November 1996, Kronos attempted to reunite the Four Horsemen. Kronos, Methos, and Silas visited the asylum, where Kronos bribed the doctor to see Caspian. Caspian killed the doctor and so the Four Horsemen reunited. They went to an abandoned submarine base in Bordeaux, France where they hid out. Kronos lays out his plan to rule the world, but Caspian is more anxious to kill.

A couple of days later, the Horsemen capture Cassandra from the hotel where she and Duncan MacLeod were staying while Duncan was visiting Methos on holy ground. Caspian and Silas, sent by Kronos to kill him, end up fighting MacLeod on a bridge. Caspian is killed, and before Silas can exact revenge, MacLeod escapes, jumping off the bridge while receiving the Quickening.

As "Famine," he has the propensity to consume living animals and possibly his victims. He eats a living roach in his cell at the asylum. He wants to eat one of the animals Kronos has caged at the submarine base (to Silas' protest). He threatens to cannibalize Duncan MacLeod at the beginning of their fight. Although not specifically stated in the show, these behaviors indicate that he possibly ate parts of his human victims, both as a serial killer in modern times and as one of the Horseman in the Bronze Age.